Guide construction for movable tank tops



Oct. 12, 1948. F. L. PLUMMER I GUIDE CONSTRUCTION FOR MOVABLE.TANK TOPS 3 Sheets- Sheet 1 Filed March 28, 1946 I INVENTOR. FRED L. PLUMM ER,

FIG.I.

ATTORNEY Oct. 12, 1948. F. L. PLUMMER 2,450,986

GUIDE CONSTRUCTION FOR MOVABLE TANK TOPS' Filed March 28, 1946 s Sheets-Sheet 2 f" I INVENTOR:

FRED L. PLUMMER,

ATTORNEY FIG. 3.

Oct. 12, 1948. FL PLUMMER 2,450,986

GUIDE CONSTRUCTION FOR MOVABLE TANK TOPS Filed March 28, 1946 i 3 Sheets-Sheet 3 INVENTOR: FRED L. PLUMMER.

ATTORNEY Patented Oct. 12, 1948 UNETED STATES PATENT FFICE.

GUIDE CONSTRUCTION FOR MGVABLE TANK TOPS of Pennsylvania Application March 28, 1946, Serial No. 657,824

4 Claims.

The invention relates to storage tanks for storing gases, or volatile liquids which have a vapor space above them, and more in particular to the type of tank having variable gas or vapor space due to a rising and falling liquid-sealed roof or top or cover construction.

A tank construction more particularly herein referred to comprises the tank proper having at the upper free end portion an annular liquid-containing sealing launder. A vertically movable cover surounds the upper end portion of the con tainer and is provided with an inner skirt portion immersed in the sealing liquid of the launder, and with an outer skirt portion surrounding the launder whereby an annular space is defined between the launder and the surrounding or outer skirt portion.

Further particularized, the invention relates to improvements in compensating devices effective between the tank proper and the roof construction for insuring proper guidance and non-binding or non-tilting movement of the roof incident to any changes of the gas or vapor volume sustaining the cover or of the liquid volume in the tank. That is to say, the invention may be said to relate to anti-tilting devices for the roof or devices to compensate for any tendency of the roof to tilt, whereby the roof is maintained substantially horizontal during vertical movement thereof.

It is among the objects of this invention to provide improved and positive acting anti-tilting devices of inexpensive, simple and sturdy construction, to insure non-tilting and non-binding vertical movement of the gas or vapor sustained cover; to provide anti-tilting devices which allowthe cover to move readily, that is with a minimum of mechanical friction up or down in response to.

volume changes of the tank content; and to em body anti-tilting devices in the tank construction in a manner whereby they are protected from rain, snow and sleet and yet accessible as to essential parts.

Another object is to provide anti-tilting guide devices which can be readily fitted in the field to tanks with gas or vapor supported covers of the structural type above refered to, and which can be easily installed as Well as easily removed for maintenance, repair or replacement.

I attain these ends by providing guide devices effective between the outer skirt and the adjacent wall of the launder, namely by providing between them spiral guides co-active with guide rollers in a manner to define spiral up and down motion of the cover, associated with additional guide rollers for insuring concentric space relationship between the cover and the tank.

According to one feature spiral guide means are stationary and fixed upon the outer wall of the 5 sealing launder, while the guide rollers engaging them are mounted accessibly upon the lower edge portion of the outer skirt portion of the movable cover.

More specifically, the lower edge portion of the outer skirt of the cover is provided with a horizontal reinforcing flange, and the guide rollers are mounted upon the underside thereof with their axis of rotation extending radially of the tank.

A specific structural feature lies in providing an 3 angular bearing bracket for the guide roller, having a horizontal shank engaging the underside of the flange, and a vertical shank engaging the vertical inner face of the adjacent vertical skirt por tion. In this way the bracket locates itself upon --the lower edgecorner portion of the skirt and thereby assumes its space relationship horizentally to the outer launder wall.

Another object is to so improve the structural design of the cover that its stressand strain. absorbing capacity is enhanced at a minimum weight of the cover, such strains being induced by the tilting and anti-tilting forces as well as by wind, unbalanced snow loads or other loads and thermal expansion forces affecting the cover.

Hence, according to one feature the circular top plate of the cover comprises a horizontal annular marginal portion to which is welded a central portion having a shallow upward bulge. The annular marginal portion has fixed to it the inner sealing skirt as well as the outer protecting and stiffening skirt carrying the anti-tilting guide roller. The annular marginal portion is constructed so as to form a rigid ring girder which resists the inward pull exterted upon it when gas or vapor 40 pressures act upwardly on the cover, maintaining its circular shape and preventing such distortions as would render the guide means inoperative. More specifically, the ring girder consists of a series of bars or shapes or deformation-resisting profiles.

According to another feature the annular marginal portion is also so constructed that one of the bars acts as a drip ring preventing vapors condensing 0n the underside of the cover from 50 entering the sealing launder.

Still another feature provides stop bars or spacers at the bottom of the sealing launder so as to prevent freezing in of the sealing skirt portion of the cover if water should have collected in the bottom of the sealing launder.

The invention possesses other objects and features of advantage, some of which with the foregoing will be set forth in the following description. In the following description and in the claims, parts will be identified by specific names for conveniences, but the are intended to be as generic in their application to similar parts as the art will permit. 1 In the accompanying drawings there has been illustrated the best embodiment of the invention known to me, but such embodiment is to be regarded as typical only of many possible embodiments, and the invention is not to be limited thereto.

The novel features considered characteristic of my invention are set forth with" particularity in the appended claims. The invention itself, howover, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodimerit when readin connection with the'accom panying drawings in which Fig. l is an elevational schematic view of the tank construction as a whole embodying the guide devices for the up and down movement of the tank cover;

Fig. 2 is a plan View of the tank construction taken on the line 2-2 in Fig. 1;

Fig. 3 is a part sectional enlarged detail View taken on the line 33'in Fig. 2;

Fig. -is'an enlarged view taken on the line i in Fig. 2;

Fig. 5 is a detailed sectional view taken on the line 5-5 in Fig. 4.

6 is a detail view of a detachable guide rollerunit taken on the line 66 in Figs. 4 and 5;

Fig. '7 is a similar detail view of the guide roller unit detached.

The tank construction as a whole embodying this invention comprises a tank proper l8 having a bottom I l and a cylindrical vertical wall 1 1 provided at its top end portion with an annular sealing launder l2 having a bottom l3'in the form of an annular angle iron from which rises'an outer cylindrical wall M of the launder reinforced at the top with an annular angle iron [5. The tank'construction further comprises a tank cover I G the top portion of which is composed of a marginal annular horizontally extending plane section I? and a central circular convex section IS fastened marginally to the annular plane section l? as by welding. The annular section I? is reinforced at its inner edge by'an annular steel strip is welded thereto. The tank is internally reinforced at the top by a system of radially extending stiffening beams 28 such as indicated in Fig. 3. These-beams 20 have an incline corresponding to the interior configuration of the top portion of the cover, and-are fastened to brackets 2| provided upon the'inner face of the vertical tank wall I l, as by means of screw bolts or welding (not shown). The cover l8 may, therefore, rest upon the beams 20, when in its lowermost position.- The beams-20 are supported by steel columns (not shown) within the tank.

From the annular plane section l1 extends downwardly a sealing skirt 22 into the sealing launder l2, the skirt being welded to the section ll as indicated at 23. With the cover in its lowermost position the extreme lower end of the sealing skirt 22 is prevented-from being frozen to the launder bottom in case of 'subzero tempera" ture by providing spacer blocks 24 of sufiicient height on the launder bottom to keep the skirt 22 out of a layer of Waterwhich might have-collected in the launder underneath the customary sealing fluid such as oil or the like contained in the launder. The cover further has an outer skirt portion 25 serving as a shielding skirt and also as part of the device for guiding the cover in its up and down movement. The outer skirt 25 is formed at its'lower end with an outwardly extending flange in the form of a peripherally extending or annular channel iron 26 welded to the skirt 25. Vertical ribs 21 reinforce the skirt 25 the upper end of which is welded as at 28 to the annular plane top section I! of the tank cover.

The guiding device for the up and down movement of the tank cover comprises a plurality, that is to say for practical purposes at least three guide units 29 equally spaced from one another as indicated by the peripheral distance d (see Fig. 2).

Each such guide unit 29, as shown more clearly in Figs. 3, 4 and 5, comprises spirally disposed guide rail means provided upon the outer face of the outer wall of the launder I2, and guide rollers coacting with the rail means and being accessibl mounted upon the lower end portion of the outer skirt 25.

Consequently a guide wait 29 comprises a pair of spiral guide rails 39 and 3| of relatively steep pitch, the guide rails being in the form of channel irons extending parallel to one another and symmetrically disposed with respect to each other whereby the flanges of the channel irons are racing each other so as to constitute a box-like crosssection offering a space within which a guide roller 32 is confined and along which it is movable in a spiral path. The roller 32 is mounted upon the inner free end of a horizontal axle 33 extending radially with respect to the tank and being welded at its outer free end 33 as well as at an intermediate point 33 to a bracket structure 34. The axle 33 thus being fixed to the cover structure I8 has a reducedinner-end portion 33 upon which is rotatably mounted the guide roller 32 between'washers 33 and 33 a cotter pin 33 being provided to secure the roller axially in place. The bracket structure 34 is further composed of a pair of vertical suspension plates 3! and 38 extending transversely of the'bearing portion 35'and welded thereto, and further of ahorizontal tie-plate 39 interconnecting the vertical plates 31 and Has by welding at 40 integrally as at 4|. The horizontal tie-plate 39 forms with the vertical plate 38 an angle section S which locates itself and hugs the lower edge or corner portion of the cover l6, this corner portion being defined by the junction of the channel iron 26 with the skirt 25. The bracket structure 34 is fastened to the cover as by a pair of screw bolts 42 connecting it with the channel iron 26'and with a pair of screw bolts 43 connecting it with the skirt portion 25.

The guide unit 29*further comprises a guide roller 43 for centering the cover It with respect to the tank. The guide roller therefore engages a flat strip 44 welded to the launder wall 14 and extendingspirally, that is parallel to the guide rails 3!] and 3|. The roller 43? rotates about an axis which is inclined with respect to the horizontal, whereby it extends at right angles to the spiral strip 44. The roller 43 is mounted upon a bolt or axle 45 carried by a bracket 46 mounted upon the inner face of the skirt portion 25 as by means of two pairs of screw bolts 41 and 48 respectively, although'disposed near the lower edge portion of the skirt 25 and therefore accessible for 5 mounting, inspection, repair or servicing from below.

With respect to the guide-roller-carrying structure 34 it will also be seen, especially from Figs. 6 and 7, that these guide roller units can be readily mounted and fitted on the job as well as readily inspected and serviced. Moreover these guide rollers in spite of their accessibility are protected in a, sheltered spot inasmuch as the outer skirt portion 25 and its lower edge portion act as shielding elements for them.

I claim:

1. In a circular storage tank construction having a vapor sustained cover adapted to rise and fall, said cover having an outer cylindrical shielding skirt surrounding the launder, and an. inner cylindrical sealing skirt substantially concentric with the outer skirt and extending into said launder and having sealing relationship therewith, guide means for stabilizing up and down movement of the cover relative to the tank comprising a plurality of at least three spiral guide rail units of relatively steep pitch provided upon the outer face of the outer wall of the launder and substantially evenly spaced from one another along the circumference of the launder, guide roller means cooperatively associated with said spiral guide rail units comprising an inverted bracket mounted upon the extreme lower edge portion of said outer skirt, a, guide roller mounted upon said bracket at the underside thereof to rotate about a horizontal axis extending radially with respect to the tank and having guide relationship with one of said spiral guide rail units, and an auxiliary guide roller mounted upon said outer skirt portion rotating about an axis extending transversely of and at right angles to the line of pitch of the spiral up and down motion of the cover and to have guiding relationship with the outer wall of said launder.

2. Guide means according to claim 1, in which said lower edge portion has a horizontal outwardly extending flange portion forming a corner portion with said outer skirt, and in which said inverted bracket comprises an angular body portion mounted to hug said corner portion whereby a horizontal part of said body portion attaches to the underside of said flange portion, and a vertical part of said body portion attaches to the adjacent inner face portion of said outer skirt.

3. A tank construction according to claim 1, in which the top portion of the tank cover comprises a marginal annular plane horizontal section and convex central circular section marginally fixed to said horizontal section, said inner and said outer skirt extending downwardly from said plane section, with the addition of an annular reinforcement at the inner edge portion of said plane annular section.

4. A tank construction according to claim 1, in which the top portion of the tank cover comprises a marginal annular plane horizontal section and convex central circular section marginally fixed to said horizontal section, said inner and said outer skirt extending downwardly from said plane section, with the addition of stop means determining the lowermost position of the cover whereby the sealing skirt is spaced from the botton of said sealing launder.

' FRED L. PLUMMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 405,702 Gadd June 25, 1889 2,383,555 Laird Aug. 28, 1945 

